1. Field of the Invention
The present invention relates to a capsule for dental restoration material, which can be applied to a site to be restored of a tooth, immediately after mixing a dental restoration material comprising two components of a powder component and a liquid component, in filling, cementing, lining and other applications for restoration of the teeth in the dental remedy field.
2. Description of the Conventional Art
In general, a dental restoration material is used for restoration of the teeth. As the dental restoration material, a two-component system material comprising a powder component and a liquid component, which are reacted with each other upon mixing, is usually used. Hitherto, this two-component system material was provided for use after appropriately weighing the powder component and the liquid component every time and mixing them with each other. However, in recent years, for the purposes of omitting a weighing operation of the powder component and the liquid component and an operation for accommodating the dental restoration material after mixing into a syringe for applying it to a site to be restored, there have been developed capsules for dental restoration material, in which certain amounts of the powder component and the liquid component are previously weighed and accommodated in an isolated state from each other, the isolated state is released at a desired time, the both components are mechanically mixed with each other by a mixer or the like, and the resulting mixed material is extruded and applied directly into a site to be restored, such as a tooth cavity, through a nozzle.
For example, in a capsule as disclosed in Japanese Patent Publication No. 38853/1991, a powder component of two components is accommodated in a mixing compartment of a container main body, and the other liquid component is charged in a bag, which is assembled in a side portion of the mixing compartment accommodating the powder component by means of a clip. The container main body has an aperture in a tip portion. This aperture can be clogged in a spherical bearing portion in a rear end portion of a distribution nozzle. Further, the distribution nozzle is kept from the outside by means of a separately formed cap, thereby preventing the powder component to leak to the outside of the mixing compartment. And, at the time of use, the clip is pushed down in a direction of the mixing compartment using a separately prepared exclusive tool, thereby smashing and breaking the bag having a liquid component charged therein; the liquid component is discharged into an interior of the mixing compartment through an aperture provided on a side wall of the mixing compartment, followed by shaking by a mixer, thereby mixing the liquid component and the powder component with each other; the spherical bearing portion in the rear end portion of the distribution nozzle is then rotated to release a passage of the distribution nozzle; and the mixed material is extruded from the distribution nozzle via a separately prepared tool by means of a pushing pressure of a piston.
In the capsule having the structure described above, as a material of the bag having a liquid component charged therein, a laminate sheet comprising an aluminum foil and a resin film is generally used. For this reason, there are various problems as follows. That is, there is a high risk that in the case where the liquid component is acidic, at the time of use, the liquid component which has flown out by the breakage of the bag dissolves the aluminum foil in an exposed broken section of the bag and mingles into the dental restoration material. Further, there may be a risk that since the bag having a liquid component charged therein is broken by a mechanical pushing pressure, a residual piece of the broken bag section faced at the aperture of the mixing compartment mingles into the mixing compartment. Still further, since the aperture on the wall of the mixing compartment having a powder component accommodated therein is clogged merely by pushing the bag having a liquid component charged therein by the clip, the sealing properties of the mixing compartment is not complete, and an exclusive tool is necessary for breaking the bag. Also, since in the distribution nozzle assembled in the tip side of the mixing compartment, an angle against the container main body is limited to a constant angle in order to ensure a passage of the mixed material, it lacks a degree of freedom, and it is impossible to exchange the distribution nozzle.
On the other hand, a two-component system capsule for mixing and discharge as disclosed in Japanese Patent Laid-Open No. 268555/1987, in which a powder component of two components is accommodated in a mixing compartment within a container main body, and the other liquid component takes a form (pillow) being wrapped by a sheet film comprising a resin, a metal foil, or a laminate comprising a resin and a metal foil. In this pillow, the strength in the main body side is previously set to be low, and a cap to be screw engaged with the container main body is assembled in the tip side of the container main body. At the time of use, when the cap is strongly screw engaged with the container main body and moved, the sheet in the container main body side of the pillow is broken, and the liquid component is introduced into the mixing compartment through an aperture provided on a center axis of the tip of the container main body, whereby it is mixed with the powder component. After the mixing, a through rod set within a nozzle provided on an extension line of the center axis of the cap is pushed in and breaks through the sheet of the pillow in the cap side, i.e., in the nozzle side, to form a discharge outlet for the mixed material. Thereafter, the through rod is removed, a piston set in an interior of the rear end portion of the container main body is moved into the tip portion side of the container main body, and the mixed material in the mixing compartment is discharged through the nozzle.
The capsule for mixing and discharge having the structure as described above involves the following problems. That is, like the case of Japanese Patent Publication No. 38853/1991, since the sheet using a metal foil or the like wrapping the liquid component is squashed by force by means of a mechanical external pressure, thereby mixing the liquid component with the powder component in the mixing compartment, there is a risk that the liquid component dissolving an aluminum in broken section of the sheet therein mingles into the dental restoration material. Further, there may be a risk that a broken piece of the sheet mingles into the dental restoration material during the rupture of the pillow by a pushing pressure, the breakthrough of the pillow by the through rod, and the discharge of the mixed material. In addition, in such a structure, the pillow having a liquid component accommodated therein is located in a second cell between the tip portion of the mixing compartment and the nozzle. For this reason, in the case where the squash of the pillow is incomplete due to inexperience in the operation, or the like, there is a risk that the liquid component remains within the pillow, and the mixed material and the liquid component are extruded in a separated state at the tip or external surface of the mixed material during the discharge of the mixed material, whereby the desired performance is not likely obtained. Moreover, with respect to the operability, there is a defect that the operation is complicated because for the discharge of the mixed material, the through rod must be removed prior to the discharge, after the pillow is broken through by the through rod being pushed into the sheet having a higher strength of the pillow.
Further, like the case of Japanese Patent Laid-Open No. 268555/1987 as cited above, Japanese Patent Laid-Open No. 43653/1988 discloses a capsule for dental restoration material in which a liquid component pack having a liquid component packed by a sheet such as an aluminum foil is aligned in an outside of the tip of the mixing compartment of the container main body; the liquid component pack is ruptured by a screw-in pushing pressure of the cap, thereby making the liquid component flow into the mixing compartment through an aperture on the center axis of the container main body and mix with the powder component; and a plunger with a tool for breakthrough of a pack provided in the rear end portion of the container main body is moved to break through a tip of the liquid component pack in the nozzle side, thereby supplying a mixed dental restoration material into a dental restoration portion. However, in this capsule, like the above-described two structures, since the liquid component pack having the liquid component wrapped by a sheet such as an aluminum foil is used, this capsule involves the following problems. That is, when the liquid component pack is pushed and ruptured, the liquid component in which the aluminum in the broken section of the sheet constituting the liquid component pack is dissolved likely mingles into the dental restoration material, and a broken piece of the liquid component pack likely mingles into the dental restoration material. Further, since the liquid component pack is located forward of the mixing compartment of the container main body, in the case where the pushing pressure is insufficient, the liquid component does not completely enter into the mixing compartment, whereby the mixing cannot be thoroughly effected. Besides, not only the liquid component remained within the liquid component pack is extruded in a separated form from the mixed material during the discharge of the mixed material, but also in a state before mixing the two components of the powder component and the liquid component, the aperture of the mixing compartment is clogged merely by means that it has come into contact with a surface having a weak strength of the liquid component pack, whereby the powder component possibly leaks out.
The invention is aimed to overcome the problems of the conventional art capsules for dental restoration material as described above and provide a capsule for dental restoration material that is free from defects including dissolution of a broken metal section of a sheet constituting a pack accommodating a liquid component of the capsule for dental restoration material by the liquid component, contamination of a broken piece of the pack as a foreign matter into the dental restoration material by pushing rupture, and retention of the liquid component within the pack by insufficient pack pushing pressure, and that is improved in the sealing properties of a mixing compartment accommodating a powder component, is small-sized, is extremely simple in the structure, is less in the number of parts, and can be operated with ease.
In order to solve the above-described problems of the conventional art, we, the present inventors made extensive and intensive investigations. As a result, it has been found that a capsule for dental restoration material for applying directly to a tooth site to be restored of a patient a mixed material prepared by mixing therein a dental restoration material comprising two components of previously weighed constant amounts of a powder component and a liquid component, having a structure comprising a capsule main body in a cylindrical shape having a mixing compartment accommodating a powder component therein, the capsule main body being provided with a first aperture forming portion to form an outlet hole for the mixed material on a center axis in a tip portion thereof; a liquid cup having a liquid component accommodation compartment accommodating a liquid component therein, the liquid cup being provided with a second aperture forming portion to form an outlet hole for the liquid component on a center axis in a tip portion thereof, being engaged with a cylindrical portion to form the mixing compartment of the capsule main body, and being provided on an external surface in the vicinity of a rear end portion thereof with a convex stopper having a size so as to inhibit the liquid cup to readily slide into the capsule main body during breaking through the second aperture forming portion to form the outlet hole for the liquid component but not inhibit the liquid cup to slide into the capsule main body when a large force is applied; a plunger having a rod-like projection for breaking through the second aperture forming portion of the liquid cup and the first aperture forming portion of the capsule main body, the plunger being engaged with a cylindrical portion with in the liquid cup; and a nozzle whose rear end portion has a shape corresponding to the tip portion of the capsule main body, the nozzle being connected to the tip portion of the capsule main body, prevents a phenomenon that the liquid component dissolves a metal of a broken section of a pack, contamination of a broken piece of the pack into the dental restoration material, and retention of the liquid component within the pack, because the pack accommodating a liquid component is not used, improves the sealing properties of the mixing compartment accommodating the liquid component therein, is small-sized and simple in the structure, is less in the number of parts, and enables to perform the dental restoration remedy with an easy operation, leading to the accomplishment of the present invention.
And, it has been found that the following embodiments are preferred. That is, when an applier engagement groove is engraved on an outer periphery side surface in the vicinity of the rear end portion of the capsule main body, it is possible to easily perform an operation in which a claw of the applier is engaged with the applier engagement groove, and the plunger is moved by a push rod of the applier, thereby making the powder component flow completely into the mixing compartment and an operation in which the mixed material as prepared by mixing the liquid component and the powder component with each other is extruded from the nozzle. When the outlet hole of the first aperture forming portion of the capsule main body and the outlet hole of the second aperture forming portion of the liquid cup are a circular hole, respectively, and a notch having a size of about three-fourth of the circumference is provided in each periphery thereof, during breaking through the aperture forming portions of the capsule main body and the liquid cup by the rod-like projection of the plunger, the whole of the aperture forming portions can be broken through with a small force without causing cut-off. Further, when the tip portion of the nozzle is tapered and curved, the mixed material can be fed into a desired small site such as a tooth cavity, without forcing a patient to open a mouth largely. Still further, when the rear end portion of the nozzle is connected to the tip portion of the capsule main body by means of an engagement of a ring-like convex portion with a ring-like concave portion having a corresponding shape thereto, the nozzle can be conveniently rotated against the capsule main body.